Patent GB-474762-A (GB)
Title: Improvements in or relating to the softening of nitrocellulose plastics and to compositions therefor
Filed: 1936-05-05
Abstract: Nitrocellulose plastics are softened by treatment with an aqueous solution of methanol and one or more branched chain aliphatic ketones which by themselves are immiscible or incompletely miscible with water.  The composition of the softening liquid is such that it is incapable of completely dissolving the nitrocellulose plastics. Preferably the ketone contains not more than nine carbon atoms and has a boiling point between 115 and 128 DEG  C.  Methyl isopropyl, ethyl isopropyl, and di-isopropyl ketones, are specified.  Mixtures of ketones particularly those obtained by the oxidation or dehydrogenation of the mixture of branched chain secondary alcohols obtainable by catalytic pressure hydrogenation of oxides of carbon, may be used. The softening liquid may contain 3--4 parts by volume of the methanol-ketone mixture to 1 part of water, and there may be 9--25 parts of ketone to 75--91 parts of methanol.  Sheets of nitrocellulose plastics including celluloid may be softened by dipping in the solution.  The softened sheets may be used for covering wood heels, toilet seats, hamper tops, high chair trays, and other articles, and they may be embossed.  Cement may be applied to the form or mould to be covered, and the softened sheet then pressed or stretched round the object and allowed to harden by evaporation of the softener.  The softening composition may also be used in the production of nitrocellulose plastic articles, leather belt compositing and other operations involving temporary softening of nitrocellulose plastics.ALSO:Nitrocellulose plastics are softened by treatment with an aqueous solution of methanol and one or more branched chain aliphatic ketones which by themselves are immiscible or incompletely miscible with water.  The composition of the softening liquid is such that it is incapable of completely dissolving the nitrocellulose plastics.  Preferably the ketone contains not more than nine carbon atoms, and has a boiling point between 115 and 128 DEG  C.  Methyl isopropyl, ethyl isopropyl, and di-isopropyl ketones are specified.  Mixtures of ketones particularly those obtained by the oxidation or dehydrogenation of the mixture of branched chain secondary alcohols obtainable by catalytic pressure hydrogenation of oxides of carbon, may be used. The softening liquid may contain 3-4 parts by volume of the methanol-ketone mixture to 1 part of water, and there may be 9-25 parts of ketone to 75-91 parts of methanol.  Sheets of nitrocellulose plastics including celluloid may be softened by dipping in the solution.  The softened sheets may be used for covering wood heels, toilet seats, hamper tops, high chair trays, and other articles, and they may be embossed.  Cement may be applied to the form or mould to be covered, and the softened sheet then pressed or stretched round the object and allowed to harden by evaporation of the softener.  The softening composition may also be used in the production of nitrocellulose plastic articles, leather belt compositing and other operations involving temporary softening of nitrocellulose plastics.